Tutorial/example on how to use `newPackageConfigJsonFileFromBuilder`

[FMorschel]

Based on #61900 and #61597, I'm proposing we add an entry to analyzer_testing or to analysis_server_plugin tutorials on how to utilise newPackageConfigJsonFileFromBuilder.

Possibly adding an example of how to use a physical folder and a memory one might be good too.

CC @srawlins

[srawlins]

Yeah I agree. Something I haven't figured out is where to focus these testing docs: in pkg/analysis_server_plugin/doc? In pkg/analyzer_testing/README? In pkg/analyzer_testing API docs?

I think we definitely need to beef up the API docs. And as the tutorial-style docs get bigger, they should probably live in pkg/analyzer_testing, not pkg/analysis_server_plugin/doc.

[FMorschel]

And as the tutorial-style docs get bigger, they should probably live in pkg/analyzer_testing, not pkg/analysis_server_plugin/doc.

Agreed.

Something I haven't figured out is where to focus these testing docs: in pkg/analysis_server_plugin/doc? In pkg/analyzer_testing/README? In pkg/analyzer_testing API docs?

Would there be any problems if we had a link under pkg/analysis_server_plugin/doc that points to a file in pkg/analyzer_testing? I don't think so. In that case, I'd definitely keep the docs in the declaring packages.

About analyzer_testing/README, I'd probably have it listing some specific docs, but have them in their own files as we are doing for analysis_server_plugin.

[srawlins]

Would there be any problems if we had a link under pkg/analysis_server_plugin/doc that points to a file in pkg/analyzer_testing?

No problem.

About analyzer_testing/README, I'd probably have it listing some specific docs, but have them in their own files as we are doing for analysis_server_plugin.

I think separate files would only be warranted if they get unwieldy. There is something to be said for CTRL+F, and also for LLMs having to look in fewer places.